21734 has 4 divisors (see below), whose sum is σ = 32604. Its totient is φ = 10866.

The previous prime is 21727. The next prime is 21737. The reversal of 21734 is 43712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21737) by changing a digit.

21734 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5432 + ... + 5435.

It is an arithmetic number, because the mean of its divisors is an integer number (8151).

2²¹⁷³⁴ is an apocalyptic number.

21734 is a deficient number, since it is larger than the sum of its proper divisors (10870).

21734 is a wasteful number, since it uses less digits than its factorization.

21734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10869.

The product of its digits is 168, while the sum is 17.

The square root of 21734 is about 147.4245569775. The cubic root of 21734 is about 27.9070044035.

The spelling of 21734 in words is "twenty-one thousand, seven hundred thirty-four".